PHASE-TRANSITIONS IN QUANTUM DOTS

We perform Hartree-Fock calculations to show that quantum dots (i.e., two-dimensional systems of up to twenty interacting electrons in an ex ternal parabolic potential) undergo a gradual transition to a spin-pol arized Wigner crystal with increasing magnetic-field strength. The pha se diagram and ground-state energies have been determined. We tried to improve the ground state of the Wigner crystal by introducing a Jastr ow ansatz for the wave function and performing a variational Monte Car lo calculation. The existence of so-called magic numbers was also inve stigated. Finally, we also calculated the heat capacity associated wit h the rotational degree of freedom of deformed many-body states.